To evaluate the surface quality of ring core spun yarns, we set up a quality measurement system that operated on the basis of a CCD camera along with specific software programs that recognised the surfaced core filaments. The acquired images were transformed to binary states and filtered through a moving window. By defining a quantitative index by means of the number of defects per length of the specimen, the effects of the processing variables such as production speed and traveller mass on the surface quality of core spun yarns were investigated. Results demonstrated that the new measuring system could be applied effectively to assess the core coverage of yarns. There existed some optimal levels of yarn production speed and traveller mass that led to a minimum occurrence of the surface defects of core spun yarns.

Wide range of fineness of ultra-fine denier PET filaments (0.2~0.01 denier per filament) were prepared and the effects of fineness on the dyeing properties of a disperse dye (CI Disperse Blue 56) were studied. The equilibrium study of the disperse dye on the fibers at various concentrations showed that the isothermal absorption was Nernst type and that the equilibrium adsorption of the dye increased with the increase in fiber fineness. Dyeing rate of the dye increased with the decrease in fiber fineness. The apparent diffusion coefficient of the dye in the ultra-fine denier fibers decreased when the fiber fineness increased because of the limited dye liquor turbulence through the compactly assembled filaments in the ultra-fine denier yarn. The temperature dependence of dye diffusion decreased with the fiber fineness.

A shape memory polyurethane (SMPU) with a transition temperature of was synthesized to investigate its fiber formation characteristics. Based on the thermal analysis a melt spinning process was designed, from which mono- and multi-filaments of SMPU fibers were manufactured. The shape memory performance of both SMPU film and fibers was evaluated using a thermo-mechanical cyclic test. The results revealed that SMPU fibers show similar shape memory behavior to that of SMPU film. The effect of post treatments such as annealing, drawing and heat-set on the shape memory performance of SMPU fibers was investigated and their effects on the micro-structural change of SMPU fibers were analyzed using a molecular configuration model. It was demonstrated that the properties of SMPU fibers can be tailored using these post treatments, thereby shape memory woven fabrics can be developed using SMPU fibers.

Chitosan/poly(vinyl alcohol)(PVA) blend films with non-toxicity, biodegradability, and biocompatibility were prepared by solvent blending method. The weight composition ratios of chitosan/PVA blend films were 100/0 (chitosan homopolymer), 75/25, 50/50, 25/75, and 0/100 (PVA homopolymer). Physicochemical properties of the prepared blend films according to various blend ratios were investigated by using universal testing machine, thermogravimeter (TGA), differential scanning calorimeter (DSC), wide angle X-ray diffractometer (WAXD), Fourier transform infrared (FTIR) spectrometer, and scanning electron microscope (SEM). The tensile stress and tensile strain of chitosan/PVA blend films increased as the amount of PVA increased. The thermal stability increased with increasing chitosan content in the chitosan/PVA blend films. The DSC curve of the PVA film shows an endotherm peak around , and the peak became smaller and broader with increasing chitosan content. The diffraction intensities of chitosan observed at 2 theta of decreased with increasing the content of PVA in the blend films, but the crystal intensities of the blend films increased as the amount of PVA increased. In the infrared spectra, the absorption band for -OH and -NH stretching vibrations in chitosan broadened and shifted obviously to lower wavenumber with the increase of PVA. Water-retention values of the chitosan/PVA blend films increased as the amount of PVA is increased owing to the hydrophilic nature of PVA. From the structural analyses, it is believed that chitosan and PVA are miscible due to the strong intermolecular hydrogen bonding.

Amorphous poly(phenylene sulfide) (PPS) films were prepared by melt-pressing virgin PPS chips of high linearity and quenching into ice water. The films were annealed at for up to 17 days and investigated by using a DSC. Both the melting temperature and heat of melting of PPS increased with increasing annealing time at , whereas the melt crystallization temperature and heat of melt crystallization decreased. Although the melting peak on heating still appeared, the melt crystallization peak on cooling disappeared after more than 10 days annealing, indicating the introduction of high degree of cross-linking. FTIR analysis and solubility tests of the annealed films also suggested the introduction of crosslinking. Increased crosslinking density refrained PPS from melt crystallization and dissolution in a solvent. Annealing at lower temperature such as for up to 24 hours resulted in increasing the tensile strength of the films significantly without crosslinking. The chemical resistance of the films was almost unaffected in strong acid and alkaline solutions at for 7 days.

PVA fiber has been used as a cement reinforcement because of its good mechanical properties and outstand-ing chemical resistance. However, excessively high interfacial adhesion between PVA fiber and cement matrix induced the fast fiber failure by stress localization at the interface. In the study, thus, we tried to modify the surface of PVA fiber by heat treatment in order to decrease the interfacial adhesion strength. Heat treatment temperature and time were varied to obtain the optimum condition for the modification. To exemine the fiber surface and interfacial conditions, various analyses were carried out including SEM, TGA, ATR, XPS, tensile properties and contact angle measurement. The interfacial shear strength between fiber and cement matrix was measured by a fiber pull-out test. The results showed that the wettability of the PVA fiber was lowered and interfacial strength was decreased by heat treatment, because OH groups of the PVA fiber were reduced.

Nylon 6 chips recycled from waste fishing nets were extruded through filters of various mesh sizes (150:, 250:, 325:, 400:) and subsequently chain extending reaction was carried out through melt-compounding with chain extenders, 2,2'-bis(2-oxazoline) (BOZ) and hexamethylene 1,6-dicarbamoyl dicaprolactam (HDC). The resultant changes in ash content, molecular weight and crystallization behavior in the modified nylon 6 samples were investigated from themogravimetric analysis, intrinsic viscosity measurement, end group titration, and differential scanning calorimetry, respectively. The thermal degradation kinetics were studied using a conventional thermogravimetric analysis at heating rates of 10, 20, 30, and . Thermogravimetric curves and their derivatives were analyzed using various analytical methods to determine the kinetic parameters for the thermal degradation of the modified nylon 6.

To obtain high performance microfiber knit wiping cloth used for manufacturing electronic devices benzyl alcohol pretreatment method was optimized. WAXD patterns of the PET, nylon and nylon/polyester filament fibers pretreated with benzyl alcohol showed stronger crystalline peak than 50d/14f fibers. Some properties including wiping efficiency of the wiping cloths made of 75d/36f filament fibers of nylon/PET(N/P) and the ones made of 50d/14f fibers were tested and compared. Results showed that water absorption rate of the former was higher than that of the latter. The former showed excellent removing efficiency of approximately 90% compared to 60% for the latter. Air particle counter analysis revealed that the former has less residue content than the latter.

Various air-filter media by using meltblown (MB) and spunbond (SB) nonwovens were structurally designed with different laying methods to obtain the relationship between structure and characteristic of air filters. Air permeability, pore size, filter efficiency and pressure drop of the designed filter media were investigated experimentally. The layer sequences of designed media showed significant factor on filter efficiency and pressure drop. The optimum filter media was determined as two layer structural design composed of calendering SB and MB nonwovens. In addition, a model equation to predict the pressure drop and filter efficiency of air filter media based on nonwovens was developed. The calculated values from the equation showed good agreement with experimental ones.

Recently electret filter media are extensively used to improve indoor air quality. However, they are significantly affected on environmental conditions such as humidity, temperature and chemical substance. This study reported the effect of humidity and temperature on the surface electric potential, filtration efficiency and pressure drop of electrically charged fiber (ECF) composites. The surface electric potential and filtration efficiency of ECF composites decreased rapidly, but pressure drop increased slightly with increasing relative humidity (RH) and temperature conditions. Effect of temperature change was more significant than RH change. Relationship between filter efficiency and surface electric potential relationship of ECF composites exhibited a quadratic function.

Recently, one dimensional structures such as nanotubes or nanofiber prepared from metal oxides draw wide range of attention because they can be used in various applications such as sensor, catalyst, filter and medical fields. In this study, iron oxide nanofibers were prepared by a sol-gel reaction and electrospinning method. To obtain iron oxide nanofibers, as-spun organic-inorganic hybrid nanofibers were calcined at a high temperature, and the iron oxide nanofibers obtained were characterized by using scanning electron microscopy, FTIR, and X-ray diffractometry. From the X-ray analysis, the crytal growth of iron oxide nanofibers was identified.

One of the serious complications that have not been solved yet in modern medicine is a postoperative tissue adhesion of internal organs. Tissue adhesions are associated with numerous postoperative complications, including pain, functional obstruction and difficult re-operative surgery. In this study, poly(-glutamic acid)(-PGA) based nanofiber sheets were prepared by using electrospinning technique to evaluate the ability of the prevention of postoperative tissue adhesion. The anti-adhesion membranes were prepared from -PGA and poly(D,L-lactic-co-glycolic acid)(PLGA) with different compositions by electrospinning. Also non-steroidal anti-inflammatory drug (ibuprofen) was incorporated during fabrication of nanofibers. Various electrospun nanofibers were characterized by SEM, FTIR, water contact angle measurement, biodegradability test, in vitro drug release profile, cell culture test, and in vivo animal study using Sprague Dawley rat model. The average diameter of the nanofibers electrospun from the various biodegradable polymer solutions ranged from 300 nm to 900 nm, approximately. From in vivo animal study, it was observed that ibuprofen-incorporated -PGA nanofiber sheet (crosslinked) was significantly effective in preventing post-surgical tissue adhesion and wound healing, probably due to the appropriate hydrophilicity preventing shrinkage of the sheet. On the other hand, PLGA nanofibrous mat was dramatically contracted in vivo due to its high hydrophobicity and resulted in insufficient coverage of wound.